And has any other LLC used that address? 

Also when you say you negotiated for all 3 of us to take over the mortgage that worries me because the "thing" taking over the mortgage should be a trust, LLC, etc. and never ever an individual person.

Its more like you type in an address and it mails in the vicinity. 

Don't trust what they give you.You can even ask to see Schedule E, not that they will comply. 

Please Break down in simple steps and how does the seller trust you enough to sign a contract?

It also lets you have more units at less addresses than you will need at SFH's.Always do a worst case scenario when you are evaluating a property when you trying to decide on going forward with a deal. 

Are you personally or the trust doing the 1031?

Zillow is usually wrong and should never be trusted for anything. 

A trusted mortgage broker told me that if I stay in a my second property for at least one night, I can consider it a secondary home versus investment property and therefore get a better interest rate. 

Both the bank address and bank name mirrored each other, it didn't allow for a bank name and address to be entered.